1. Field of the Invention
The present invention relates to a liquid crystal display module and a method of driving the liquid crystal display of such a module so as to reduce the overall power consumption.
2. Description of the Related Art
Liquid crystal displays are well known using a two-dimensional array of liquid crystal cells in which the cells share a plurality of signal lines in one direction and are selectively enabled by gate lines in a perpendicular direction. Drive circuits are provided which use the gate lines to enable respective sets of liquid crystal cells. The signal lines are then used to provide video signal levels to the enabled cells to charge those cells to the level required to give those cells their desired brightness.
It is usual to group the liquid crystal cells together to form image pixels. Each image pixel would typically include three liquid crystal cells corresponding respectively to red, green and blue. The red, green and blue liquid crystal cells of a pixel are provided on the same gate line and, indeed, can be driven by the same video signal. In particular, with a gate line enabling all of the liquid crystal cells of the pixel, the video signal is provided first to the red liquid crystal cell by means of its signal line, then to the green liquid crystal cell by means of its signal line and finally to the blue liquid crystal cell by means of its signal line.
The liquid crystal cells are normally all connected (on an opposite side to switches operated by the gate lines) to a common line which usually takes the form of a plate (COM plate) across the entire area of the liquid crystal display. The potential on the common line is varied in steps as a square wave so that the required inversion of sub-pixels or pixels occurs. Various forms of inversion are known: 1F frame inversion where all of the liquid crystal cells of a frame have the same potential for each frame, but the potential is changed from frame to frame; 1H inversion where all of the liquid crystal cells of a horizontal line have the same potential, but are inverted from line to line and frame to frame; and dot inversion where adjacent liquid crystal cells have opposite potential and are also inverted from frame to frame.